1. Technical Field of the Invention
The present invention relates to a method of inspecting a conductor pattern as well as to electro-optical devices, and more specifically to a pattern structure which can be suitably implemented as an electrode pattern or a wiring pattern formed on a substrate constituting a liquid crystal panel and to a method of inspecting such a pattern.
2. Description of the Related Art
A typical liquid crystal device is formed by a pair of transparent substrates attached together via a sealant, with liquid crystals filled in the space between the two substrates and surrounded by the sealant, i.e., a liquid crystal sealed area.
An example of liquid crystal device construction is shown in FIG. 4 and FIG. 5. FIG. 4 is a perspective plan view which schematically illustrates the planar structure of a liquid crystal device 10, while FIG. 5 is an expanded sectional view schematically showing the structure of the liquid crystal device 10 in the vicinity of an extended area 11s. The liquid crystal device 10 is defined by a pair of transparent substrates 11 and 12 attached together via a sealant 13, wherein the transparent substrate 11 is made somewhat wider than the transparent substrate 12 so as to have an extended area 11s projecting horizontally beyond one end of the transparent substrate 12. The rectangular interior of the sealant 13 constitutes a liquid crystal sealed area A.
Inside the liquid crystal sealed area A, transparent electrodes 11a are formed on the transparent substrate 11. The transparent electrodes 11a passes beneath the sealant 13 and is pulled onto the surface of the extended area 11s to form wiring lines 11b. Within the scope of the liquid crystal sealed area A, an overcoat film 15 is formed over the transparent electrodes 11a, and an alignment film 16 is further formed over the overcoat film 15. Meanwhile, transparent electrodes 12a are formed on the transparent substrate 12. The transparent electrodes 12a extend in the direction orthogonal to the transparent electrodes 11a, and then leads up to where the sealant 13 is formed. On the transparent electrodes 12a, an alignment film 17 is formed. In between the alignment films 16 and 17, liquid crystals (not shown) are filled, which will be aligned in accordance with the surface conditions of the alignment films 16 and 17.
On the extended area 11s, wiring lines 11c are formed on both sides of the wiring lines 11b in a particular pattern. The wiring lines 11c extends on the transparent substrate 11 up to where the sealant 13 is formed. The sealant 13 is made of resin materials containing conductive particles, and exhibits anisotropic conductivity, i.e., is made electrically conductive only in the depth direction (gap direction) of the substrates, by being pressurized between the transparent substrate 11 and the transparent substrate 12. The transparent electrodes 12a and the wiring lines 11c vertically overlap at a vertically-conductive crossover 13b of the sealant 13, and thus are electrically connected via the vertically-conductive crossover 13b. 
The wiring lines 11b and 11c are electrically connected via an anisotropic conductive film 8 to the output terminals (not shown) of the driver IC 18 for driving the liquid crystal device 10. On the extended area 11s, a terminal pattern 11d is also formed. One end of the terminal pattern 11d is electrically connected to the input terminals of the driver IC 18 via an anisotropic conductive film 8, while the other end of the terminal pattern 11d is electrically connected to wiring members 9 of a flexible wiring board, a tape automated bonding (TAB) substrate, etc.
The wiring lines 11b and 11c on the extended area 11s are formed with a small line width and in a fine pitch, and hence are vulnerable to dust and acids and also involves the danger of galvanic corrosion. Thus, after mounting the driver IC 18 and the wiring members 9, the overall mounting plane of the extended area 11s is covered with resin mold 19 containing silicone resin or the like.
In the liquid crystal sealed area A, the transparent electrodes 11a and the transparent electrodes 12a are arranged in a matrix to form a display driving area E. The display driving area E allows to display particular images in accordance with the potentials supplied to each of the transparent electrodes 11a and transparent electrodes 12a. The liquid crystal sealed area A also includes a non-driving area F (non-active area) surrounding the display driving area E (active area). In the non-driving area F, dummy conductors 11f are formed to constitute a dummy pattern 11F. FIG. 6 is an expanded plan view showing a part of the display driving area E and the non-driving area F. The non-driving area F essentially need not be provided with electrodes for driving the liquid crystal device. In the absence of the electrodes, however, the non-driving area F would have a thicker liquid crystal sealed area than that of the display driving area E, and the orientation of the liquid crystals would be altered, resulting in a different appearance from that of the display driving area E. Accordingly, as mentioned above, a dummy pattern 11 F is formed which are provided with a plurality of dummy conductors 11f, such as dummy electrodes and dummy wiring lines, having no external connections. The dummy conductors 11f are formed at the same time and with the same material as the transparent electrodes 11a, the wiring lines 11b and the wiring lines 11c. 
During the manufacturing process of a liquid crystal device as described above, after the transparent electrodes 11a, wiring lines 11b and 11c are formed on the transparent substrate 11, a pattern inspection may be performed to ensure that no short circuit occurs between any of the electrodes or wiring lines. In a typical pattern inspection, as shown in FIG. 6, a pair of probes 3a and 3b are simultaneously made to contact respectively on one of two mutually-adjacent transparent electrodes 11a to check whether there occurs a short circuit between the two transparent electrodes 11a. The inspection is performed for each set of two adjacent transparent electrodes 11a by progressively moving the probes 3a and 3b to the next respective transparent electrodes 11a one by one in the array direction of the transparent electrodes (right-and-left direction as viewed in FIG. 6). If a short circuit is observed between any of the transparent electrodes 11a, either the short-circuited part is repaired, or the transparent substrate 11 is abandoned as defective.
In the inspection process, the relative position of the pair of probes 3a and 3b is so prescribed that the probes 3a and 3b are spaced in the array direction of the transparent electrodes 11a (left-and-right direction as viewed in FIG. 6) by an amount equivalent to the pattern pitch of the transparent electrodes 11a in order to ensure that each of the probes 3a and 3b will contact respectively on one of two adjacent transparent electrodes 11a. Further, the probes 3a and 3b are so arranged to have a relative deviation in the extending direction of the transparent electrodes 11a (top-and-bottom direction as viewed in FIG. 6) in order to ensure a sufficient interval between the probes 3a and 3b, which serves to prevent short-circuiting between the probes 3a and 3b per se and to facilitate fixing of the probes.
In a conventional inspection process as described above which progressively inspects each set of two adjacent transparent electrodes 11a, a tester 3 having the probes 3a and 3b, as shown in FIG. 8, while maintaining a fixed interval between the probes 3a and 3b, performs progressive scanning in the array direction of the transparent electrodes 11a (right-and-left direction as viewed in FIG. 8) by having each of the probes 3a and 3b contact respectively on one of two adjacent transparent electrodes 11a in a repetition by the pitch of the transparent electrodes 11a. The dummy pattern 11F, if formed in the array direction of the transparent electrodes 11a (to the right as viewed in FIG. 8) is typically constituted by dummy conductors 11f which are wider than the transparent electrodes 11a and rather long in shape. This causes the probes 3a and 3b to contact simultaneously on a single dummy conductor 11f to get short-circuited. Thus, a short circuit is detected because of the dummy conductor 11f even if the non-dummy transparent electrodes 11a are non-defective. FIG. 7 is a graph illustrating a progress of a conventional inspection of an electrode pattern or a wiring pattern. On encountering dummy conductors 11f during the inspection process as described above, the probes 3a and 3b get short-circuited. Then the tester 3 detects an abnormal test result as at W in FIG. 7, thereby erroneously determining that there exists a pattern defect. It may be figured out that the non-dummy transparent electrodes 11a are actually non-defective, but only through a laborious work of analyzing test results for each substrate pattern.
Accordingly, in order to overcome the above-described problem, it is an object of the present invention to provide a method as well as a structure which prevents erroneous detection resulting from a dummy pattern in an inspection of a conductor pattern.